Why am I depressed w/ low self-esteem

I am currently a freshman in college. I am in a good sorority, I was a cheerleader in high school, and my family is well-off. I know that I have absolutely no reason to suffer from depression or low self-esteem, but somehow... I am completely miserable. On the outside, I appear to be OK... but on the inside, I am an absolute mess.

Ten minutes ago, I went off at my parents for no reason. Whenever they speak to me, I sound like a three year old. I complain about everything and pretty much everything that they say to me drives me up the wall. I know that they really do mean well, but it is so hard to act normally. Going off at them is becoming an instinct and I would do anything to fix it and be able to show some respect. Right now, I am sitting in our room in the Hard Rock Hotel on a family vacation. Instead of being appreciative, I've been a complete b*tch this whole time. I am nineteen years old and I shouldn't have to act this way about my parents.

In public, I'm paranoid. I feel like everyone is looking at me and that everyone else is so much better off than I am. I know that this isn't true, but this is what I've believed since I've been very little. It's pretty much destroyed my self esteem. Since I'm in college now and on my own, it's been showing. Although I do consider myself to be socially literate being that I got myself into a good sorority, I am having some issues with friends, with group situations in classes, and with having enough confidence to be persuasive.

Paranoid that my old dorm "hated me" since girls would always knock on my door asking for my roommate... and completely ignoring me, I moved to another dorm where I THOUGHT that I was well-liked. I did it out of loneliness and a longing to be surrounded by friends like I was back in high school. Well, I was wrong. After moving, I found out that, once again, I was in almost the same situation. I once again felt like everyone "hated me" and, on top of that, thought that I was the "crazy girl" for moving mid-year. I know that it's highly doubtful anyone really cares that I just moved in and that people really do hate me... it's hard not to think about it/worry about it when trying to make friends.

When I'm in a state of extreme mental imbalance, I have problems with inattention... which, in turn, affects my school work. Some people think that, at times, I can act a little "spacey" or take down information completely wrong. I know that at little bit of inattention isn't anything out of the ordinary, but I feel like mine is excessive whenever I compare myself to other people. I often find myself staring out into space whenever I'm being asked an important question and I often "blank out" on tests, etc. I know that I'm not stupid being that I got into a highly respectable university, it's just getting harder and harder for me to balance my moods so that I can do well in school.

I have also gone days without showing up to class for no reason other than "not feeling like it" or just being angry and wanting to rebel. I know that it is my freshman year of college and I should be more mature than this by now, so I feel like my own behavior is unacceptable. I think it is OK to not go to class if I have a legitimate reason (I even consider GBD an legit reason... if anyone know what I am referring to...), but I feel like my excuses for everything are unacceptable and I really am suffering unfortunate consequences. I say this now, and then a week from today I'll get myself into another mental state where I don't want to go to class. It's an endless cycle and I'm sick of it...

The past few months, I have been having actual panic attacks, anger fits, etc. I've been screaming at people... pushing people... yelling at people and basically taking out any anger that's been building up my entire life. I've never gone to this extreme before and I'm very worried. I did feel this way sometimes in high school, but I would take my anger out on things like punching bags... or go to tumbling class... or go run... or do something where I could take all of my frustration out. Now that I don't have a set place to vent, I take it out on other people and, as a result, I'm suffering the consequences.

When I'm not in a "maniac" state, I'm a laid-back, agreeable person. I'll listen to anyone and I really do try to be a great friend. I'm doing whatever I can right now to fix these problems, but I'm just wondering if anyone out there is going through the same thing.

I've been thinking that maybe it could be a very mild form of bipolar II disorder... or maybe OCD. I come from a background where "crazy people" are stereotyped as societal misfits and belong in an insane asylum. I know that this stereotype ISN'T true at all, so I don't even know where to begin with treatment.

I would love to hear from other people about their experiences and wonder if anyone has a story similar to my own.

Sorry this post was kind of long.